Radiator Cap - 1948 vs. 1955

Tue Jun 18, 2013 4:00 pm

Hi all - the cap on our 48 is a no pressure cap. Dad thinks the 55 is a pressure cap, so he added pieces of rubber down in the filler hole, so the cap would seal. What cap should be used on our 1955 cub?

Ken

Re: Radiator Cap - 1948 vs. 1955

Tue Jun 18, 2013 4:19 pm

No pressure.

Re: Radiator Cap - 1948 vs. 1955

Wed Jun 19, 2013 10:18 am

Same radiator cap from 1947 through 1979... The Cub was always a non-sealed "thermosiphon" system for cooling, no water pump.

Re: Radiator Cap - 1948 vs. 1955

Wed Jun 19, 2013 10:40 am

Matt Kirsch wrote:Same radiator cap from 1947 through 1979... The Cub was always a non-sealed "thermosiphon" system for cooling, no water pump.

Not a completely true statement. At least three different caps were used including 2 pressure caps. Thermosiphon does not mean a pressure cap cannot be used.

Long Stripe Cubs came with pressure caps as an option, at least as they are listed in the parts book as a "special". (edit) 117536C1 was the standard Long Stripe cap but I am not sure what that is. Mine came with a 7lb cap but it may have been replaced.

The book shows 4 different caps. I know they had 1 in and 3/4 inch deep water necks for a while so that accounted for 2 of the pressure caps.

Not that this matters to the original question- all non pressure from the Factory in the 50's, but I have always had a pressure cap on my 52.

Re: Radiator Cap - 1948 vs. 1955

Wed Jun 19, 2013 12:02 pm

bob in CT wrote:

Matt Kirsch wrote:Same radiator cap from 1947 through 1979... The Cub was always a non-sealed "thermosiphon" system for cooling, no water pump.

Not a completely true statement. At least three different caps were used including 2 pressure caps. Thermosiphon does not mean a pressure cap cannot be used.

Long Stripe Cubs came with pressure caps as an option, at least as they are listed in the parts book as a "special". (edit) 117536C1 was the standard Long Stripe cap but I am not sure what that is. Mine came with a 7lb cap but it may have been replaced.

The book shows 4 different caps. I know they had 1 in and 3/4 inch deep water necks for a while so that accounted for 2 of the pressure caps.

Not that this matters to the original question- all non pressure from the Factory in the 50's, but I have always had a pressure cap on my 52.

Thanks Bob - Since I made this post, I noted that TM tractor has 3 caps for the FCubs and different one's for the number series. It's clear now why the different caps exist given the .75 and 1 inch necks. TM lists the 7lb caps as International Cub, 1975 - 1979 (serial# 248125 and above) and the non-pressure cap from 1947 to 1975. If you've always run your 52, with a 7lb cap, I guess all I need to do is purchase the correct depth cap for the nexk on my 55.

As always, thanks for all the help, Ken

Re: Radiator Cap - 1948 vs. 1955

Wed Jun 19, 2013 12:14 pm

just remember if your radiator is questionable use a non pressure cap or you could create leaks.